<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>菜鸟教程</title>
  <script type="text/javascript">
    // 真值
    console.log(Boolean(true))
    console.log(Boolean({}))
    console.log(Boolean([]))
    console.log(Boolean(123))
    console.log(Boolean('foo'))
    console.log(Boolean(new Date()))
    console.log(Boolean(-123))
    console.log(Boolean(3.14))
    console.log(Boolean(-3.14))
    console.log(Boolean(Infinity))
    console.log(Boolean(-Infinity))

    // 假值
    console.log(Boolean(false))
    console.log(Boolean(null))
    console.log(Boolean(undefined))
    console.log(Boolean(0))
    console.log(Boolean(0n))
    console.log(Boolean(NaN))
    console.log(Boolean(''))
    console.log(Boolean(""))
    console.log(Boolean(document.all))
    console.log(Boolean())
    console.log(Boolean())

  </script>
  <style type="text/css">

  </style>
</head>

<body>
  <div>

  </div>
</body>

</html>